Feeding device for rock drills



1941- w. A. MORRISON ETAL 2,265,444

FEEDING DEVICE FOR ROCK DRiLLS Filed April 12, 1940 ENTORS vfiler/mom gee/ye Hfuehmr l mum: and BY 6 THEIR ATTORNEY Patented Dec. 9, 1941 s' PATENT OFFICE FEEDING DEVICE FOR DRILLS William A. Morrison, Boston, 21., and George H.

Foehrer, l'hilliplburg, N. .I., anlgnorl to Ingeraoll-Band Company, New York, N. Y., a com ration of New Jersey Application April 12, 1940, Serial No. 329,210

IOOlaims.

This invention relates to rock drilling mechanism, and more particularlyto a feeding device for advancing arock drill toward and retracting it from the work.

In a more specific sense, the invention relates to a feeding device for rock drills of the drifter type in which the rock drill is actuated along a guide member by a feed screw rotated by a fluid actuated rotary motor. In practice the guide member is attached to a supporting device, as for example a bar or frame and the rotary motor rotates the feed screw to advance the rock drill toward the work in accordance with the penetration of the working implement thereinto.

In operations in which a group of rock drills actuated by rotary feeding motors are mounted on the same has or frame it has been found that the combined forces of the feeding motors tend to thrust the supporting member away from the work. Even highly rigid supports are deflected or bent to some extent, and when some of the rock drills a battery have completed their run of drilling the thrust of the mounting must be borne by the drilling mechanisms still in operation. This condition often forces the operating working implements so hard against the chuck parts of the rock drills that they tend to tilt within their housings and become worn excessively as a result.

It is accordingly an object of the invention to equip the feeding mechanism with a cushioning member that will yield to relieve excessive pressure against the chuck parts of the rock drill.

Another object is to automatically cut oil the power to the feeding motor in the event that the pressure against thechuclr parts of the rock drill becomes excessive.

Another object is to automatically efiect resumption of feeding movement after the pressure on the chuck parts has been relieved.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure l is a longitudinal side view. partly broken away, of a rock drill, its guide member and a rotary feeding motor for actuating the rock drill along the guide member,

Figure 2 is a longitudinal view, partly broken away, of a rotary feeding motor and a fragmentary portion of a rock drill to which the feed screw of the motor is threadedly connected,

l igures 3, 4 and 5 are transverse views taken through Figure 2 on the lines 3-3, 4-4 and 6-5, respectively.

Referring more particularly to the drawing and I at first to Figure 1, the drilling mechanism designated in its entirety by 2o, comprises a rock drill 2| mounted upon a guide member in the form of a shell 22 and at the rear end of the shell 22 is a feeding motor 23 for actuating the rock drill 2| longitudinally, of the shell through the instrumentality of a feed screw 24.

The shell 22 maybe of a well known type having 'a-cone it for cooperation with a suitable clamping device (not shown) whereby the drilling the shank end it of a drill steel 32 having lugs 3 to slidably interlock with the chuck.

The chuck so is of the rotatable type to which rotary movement may be transmitted by suitable mechanism (not shown) incorporated in the rock drill in a well known manner, and in the chuck 30 is a chuck bushing 23%, the front end of which acts as an abutment for the lugs 3b to limit the distance which the working implement may extend into the rock drill.

The cylinder is? of the rock drill carries a lug 85 located between the ribs 28, and in the lug 35 is a .ieed nut as that is in threaded engagement with the feed screw 2t and locked securely in position by a nut 3i seating against the end of'the cyl= inder 2?.

The motor as, which is attached to the rear end of the shell 22 by standards 28, is of the fluid actuated rotary vane type. It comprises a casing 39 having lugs to to receive the standards 38 and is bored to provide a chamber M for the accommodation oi a piston or rotor 42. The rotor 42 is disposed eccentrically within the chamber it and is provided with a plurality of radial slots 43 containing vanes 4% against which pressure fluid acts for rotating the rotor.

The motor 23 is of the reversible type and the direction of rotation thereof is controlled by a "valve 45 rotatable in a valve chamber 46 adjacent the chamber ii. The valve 45 has a bore 41 and a port 48 opening into the bore 41 and adapted to register with passages 49 and 50 leading toopposite sides of the point of minimum clearance between the wall of the chamber 4i and the outer surface of the rotor.

In the periphery of the valve 48 is a partly annular groove ii to register selectively with. the passages 49 and 88 for placing said passages in communication with a free exhaust port 82 leading from the valve chamber 48 to the atmosphere. The valve 48 is of less length than the valve chamber 48 and is held in one end thereof by a nut 83 threaded on a projecting stem 84 of the valve for holding a lever 88 thereon. The chamber 4i is also provided with free exhaust ports 58 and 81 arranged on the opposite sides of the plane of maximum clearance between the wall of the chamber 4| and the periphery of the rotor 42.

The rotor 42 is mounted upona shaft 58 journaled in the rear and front heads 59 and 88 of the motor casing and is secured to the rotor by a key 8i. The shaft 88 extends forwardly of the head 88 and carries a sun pinion 82 that meshes with planet pinions 83 meshing with an internal gear or, as illustrated, teeth 64 on the inner surface of a casing 85 seating against the front end of the head 88. The pinions 83 are mounted upon spindles 88 seated in a carrier 81 rotatable in the casing 88.

On the front end of the carrier is a skirt 88 which is journaled in a bushing 89 in the easing 65, and on the inner surface of the skirt 88 are longitudinally extending ribs 18 that mesh with ribs ii on the periphery of a sleeve 12 keyed to the rearward end of the feed screw 24 and held thereon by a nut 13. The sleeve 12 is slidable longitudinally of the carrier 81 as is, of course, also the feed screw 24 of which the front end." is journaled, slidably, in a bearing 15 carried by the shell 22.

The rear end of the feed screw adjacent the sleeve 1: lies in a bushing 18 arranged in a boss 11 in the casing 85 and having an external flange 18 that seats against the front end of the boss 11. The boss 11 projects into a head I9 arranged at the front end of the casing 68 and cooperates with the head 19 to define a pressure chamber 88 in which is arranged a piston 8| that serves to oppose the rearward movement of the feed screw with respect to the motor.

The piston 8i encircles the rearward end of the feed screw 24. It is slidable relatively to the feed screw and is slidably interlocked with the head 19 by a. key 82 seated in 'a reduced forward extension 83 of the piston, The extension 83 may, as shown, protrude from the front end of the head I9 and has an internal shoulder the collar 88 of the feed screw.

the head 18, the casing 88 and the motor casing and its heads to the front end of the valve chamber 48 forwardly of the valve 48 so that the bore 41 will be in constant communication with thepassage 92.

The passage 82 is so located with respect to the pressure chamber 88 that it will be fully uncovered when the piston 8i is in its foremost limiting position, and a groove 89 of gradually diminishing flow area leads rearwardly along the wall of the pressure chamber 88 from the passage 92 to a point intermediate the passage 92 and the rear end. of the pressure chamber 88.

In this way, when the piston 8| is thrust rearwardly across the passage 92 the flow of pressure fluid from the pressure chamber 88 to the passage 92 will be gradually cut 08!.

During the normal operation of the drilling mechanism and with the valve 48 in a position to admit pressure fluid into the motor to cause feeding movement of the feed screw 24, the pressure fluid flowing through the pressure chamber 88 will hold the piston 8i in the front end ofthe pressure chamber 88 and the shoulder 84 against The motor will then rotate the feed screw to maintain the percussive element of the rock drfll in the correct 84 to abut the rearward surface 88 of a collar 88 carried by the feed screw. A sealing ring 81 is arranged in the periphery of the piston 8| and a. sealing ring 88 is preferably arranged in the flange 18 to seat against the inner surface of the piston 8i for preventing leakage of pressure fluid from the chamber 88 along the boss 11. A vent 89 in the head 19 communicates the front end of the chamber 88 with the atmosphere.

The pressure fluid to which the piston 8i is subjected is conveyed into the pressure chamber 88 by a passage 98 in the casing 85 and is supplied to the passage 98 .by a conduit 9|. As a preferred arrangement, the pressure fluid used for operating the motor also passes through the pressure .chamber 88. To this end a passage 92 intermediate the ends of said chamber through against the working implement becomes excessive, as when the mounting supporting the drilling mechanism shifts to a position in which a ortion of its weight and that of the drilling mechanisms leans against the drill steels, the

feed screw will be moved rearwardly against the force of the pressure fluid acting against the piston 8i and in that way the pressure against the chuck parts will be relieved.

This rearward movement of the feed screw will cause the piston 8i to move into the plane of the passage 92 andth'us partially cut oil the flow of pressure fluid to the motor 23 and there-v by reduce the power of the motor. Should the pressure of the drilling mechanism and its mounting against the working implement be unduly great the piston 8i will be moved still further rearwardly until it completely-overlies the passage 92 and cuts off the flow of pressure fluid tinue independently of the motor until all the parts are restored to a position in which little or none of the weight of the drilling mechanisms and their mounting leans against the working implement, and the piston 8| will then be in position to permit the flow of a full supply of pressure fluid to the motor for rotating it.

After the working implement has been driven into the rock to the limit of its extent, or when ing the motor.

a drill hole has been completed, the valve 45 is rotated to its other extreme position for revers- The feed screw will then be turned in an opposite hand direction for retracting the rock drill to its starting position. 4

We claim: 1. In a feeding device, the combination of a guide member and a rock drill slidable thereon, a rotary feeding motor for the rock drill, a feed screw slidable longitudinally in the guide member threadedly engagirg the rock drill, and being slidably interlocked with the motor, and means subjected to pressure fluid for cushioning the endwise movement of the feed screw with respect to the motor. 1

2. In a feeding device, the combinatio'nof I guide member and a rock drill slidable thereon,

a rotary feeding motor for the 'rock drill attached to the guide member, a feed screw slidable longitudinally in the guide member threadedly' engaging the rock drill, means slidably interlocking the feed screw ,with the motor, and means on the feed screw subjected to pressure fluid for pushioning the endwise movement-of the feed screw.

- 4. In a feeding device, the-combinationnof a guide member and a rock drill slidable thereon,

a rotary feeding motor for the rock drill having a casing attached to the guide member, a feed screw slidable longitudinally in the guide member andthe casing and being threade'dly connected to the rock drill, means to slidably interlock the feed screw to the motor, a pressure chamber in the casing, and a piston in the pre'ssure chamber subjected to pressure fluid to cushion the endwise movement of the feed screw toward the motor.

5. In a feeding device, the combination of a guide member and a rock drillslidable thereon, a rotary feeding motor for the rock drill having a casing attached to the rear end of the guide member, a feed screw slidable longitudinally in v 6. In a feeding device, the combination of a guide member and a rock drill slidable thereon,

a fluid actuated rotary feeding motor for the rock drill, a feed screw operatively connected with the motor and the rock drill, reciprocatory valve means for controlling the flow of pressure a fluid actuated rotary feeding motor for the rock" drill, a feed screw operatively connected with the motor and the rock drill and being slidable longitudinally of the motor, and means actuated by the feed screw upon endwise movement thereof for controlling the flow the motor.

8. In a feeding device, the combination of a guide member and a rock drill slidable thereon,

of pressure fluid to a fluid actuated rotary feeding motor for the rock drill having a casing attached to the guide member, a feed screw operatively connected with the motor and the rock drill and being slidable longitudinally of the motor, and means in the casing subjected to pressure fluid for cushioning ,the endwise movement of the feed screw and being actuated by the feed screw to control the flow of pressure fluid to the motor.

9; In a feeding device, the combination of a guide member and a rock drill slidable thereon,

motor and the rock drill and being slidable longitudinally of the motor, a pressure chamber in in the casing, a supply passage leading from the pressure chamber to the motor, and a piston in the pressure chamber subjected to pressure fluid for cushioning the rearward movement of the feed screwand being actuated by the feed screw to control the supply passage.

10. In a feeding device, the combination of a guide member and a rock drill' slidable thereon, a fluid actuated rotary feeding motor for the rock drill having a casing attached to the guide member, a feed screw operatively connected with the motor and the rock drill and being slidable longi-- tudinally of the motor, a pressure chamber in the casing, a supply passage leading from the pressure chamber to the motor, a shoulder on thefeedscrew, and a piston in the pressure chamber slidable on the feed screw to engage the shoulder forcushioning the rearward movement of the feed screw and being actuated by the feed screw to control the supply passage.

fluid for cushioning the rearward movement of the feed screw.

) WILLIAM A. MORRISON.

GEORGE H. FUEHRER. 

